Diastolen

Diastolen is the plural form of diastole in certain languages, though in English the term is usually diastole (with diastoles used rarely). Diastole refers to the phase of the cardiac cycle when the heart muscle relaxes and the ventricles fill with blood. It follows systole and ends with the onset of the next contraction.

During diastole, filling occurs in several subphases. Early rapid filling happens as the ventricle pressure falls below atrial pressure. This is followed by diastasis, a period of slower filling, and, near the end of diastole, atrial contraction (atrial kick) adds a final amount of blood to the ventricles. The duration of diastole lengthens at slower heart rates and shortens as heart rate increases.

Coronary perfusion largely occurs during diastole. Because the heart muscle relaxes, the coronary arteries receive blood flow when aortic pressure drives blood into the coronary circulation, whereas systole can compress these vessels and reduce flow.

Clinically, diastolic function is assessed to identify diastolic dysfunction or diastolic heart failure, conditions characterized by impaired ventricular filling and raised filling pressures, often in the setting of hypertension, aging, obesity, or cardiomyopathies. Echocardiography commonly evaluates diastolic function using parameters such as Doppler E/A ratio, tissue Doppler e' velocity, and left atrial size.

Diastolic pressure is the arterial pressure during diastole and is a component of the standard blood pressure reading (systolic over diastolic). In summary, diastolen describes the heart’s relaxation and filling phase, essential for proper cardiac output and coronary blood supply.